RasGAP (Ras GTPase activating protein) or RAS p21 protein activator 1 , also known as RASA1, is a 120-kDa cytosolic human protein that provides two principal activities:Inactivation of Ras from its active GTP-bound form to its inactive GDP-bound form by enhancing the endogenous GTPase activity of Ras, via its C-terminal GAP domain;Mitogenic signal transmission towards downstream interacting partners through its N-terminal SH2-SH3-SH2 domains.